Cigarette making machine

ABSTRACT

A cigarette making machine includes a channel (10; 100; 204) through which tobacco is pneumatically conveyed to form a cigarette filler stream (15; 209) on a conveyor (12; 130; 200) at the outlet of the channel, a first louvre (20; 110; 214) through which some of the air entering the channel through its inlet end is drawn from the channel while tobacco continues towards the conveyor, and a second louvre (22; 120; 216), closer than the first louvre to the outlet end of the channel, through which an additional amount of the air entering the channel is drawn while the tobacco continues towards the conveyor. The channel (202) may be arranged to extend around a cylinder with an inclined axis (208) so that upward movement of the tobacco is converted into approximately horizontal movement with a substantial component in the direction of movement of the conveyor (200) on which the tobacco collects to form a cigarette filler stream (209).

This invention is concerned with cigarette making machines of the typeincluding a channel through which tobacco is conveyed pneumatically toform a cigarette filler stream on a conveyor at the outlet of thechannel. An example of such a machine is described in British Patentspecification No. 916141. The machine described in that specificationincludes a louvre through which some of the air entering the channel isextracted while tobacco continues towards the conveyor; the use of suchlouvres has been common in Molins cigarette making machines for manyyears.

According to one aspect of the present invention, a cigarette makingmachine includes a channel through which tobacco is pneumaticallyconveyed to form a cigarette filler stream on a conveyor at the outletof the channel, a first louvre through which some of the air enteringthe channel through its inlet end is drawn from the channel whiletobacco continues towards the conveyor, and a second louvre, closer thanthe first louvre to the outlet end of the channel, through which anadditional amount of the air entering the channel is drawn while tobaccocontinues towards the conveyor.

Effectively, the second louvre according to this invention correspondsto the louvre used hitherto, the difference being in the provision ofthe first louvre. Owing to the presence of the first louvre, the airvelocity beyond the first louvre is reduced compared with the velocityof air entering the channel, and this results in a reduction in thetobacco velocity on impact with the conveyor. The reduced impactvelocity is beneficial in that it reduces tobacco breakage. Thearrangement can be such that, compared with previous machines, the airvelocity entering the channel is substantially unchanged, e.g. atapproximately 60 feet/sec (approximately 18.3 meters/sec), so as toachieve the desired separation of tobacco particles and possibly alsodeflection in accordance with the second aspect of this invention, whileallowing the tobacco to arrive at the conveyor with a much lowervelocity (well below 30 feet/sec).

In this context the term "louvre" refers generally to an air outletcomprising one or more openings so arranged that air is drawn throughthe opening or openings without any significant amount of tobacco, whichinstead remains in the channel and continues its movement towards theconveyor. Each louvre preferably comprises a number of openings, theparts between the openings being preferably inclined as in aconventional louvre (as shown in British Patent specification No.916141).

As has been common practice in Molins machines, the flow of air throughthe channel is preferably induced by suction; in the present inventionsuction is preferably applied to both louvres. This invention will bedescribed in such terms, but it should be understood that it isconceivable, as an alternative, to use above-atmospheric pressure toinduce the air flows occurring in the present invention, and thefollowing description and claims should be construed accordingly.

In the present content the term "carpet" refers to a stream of mainlyseparated particles of tobacco having a width (transverse to thedirection of movement of the tobacco) considerably greater than thethickness.

One application of this aspect of this invention is concerned witharranging that the tobacco arrives at the conveyor with a significantcomponent of movement in the direction of movement of the conveyor. Theconveyor may, for example, be a band which is inclined to the horizontalby up to 15 degrees so as to convey the cigarette filler streamdownwards onto the web of cigarette paper in which the stream issubsequently enclosed. Accordingly, if the tobacco is to have acomponent of movement in the direction of movement of the conveyor, itspath must be inclined to the vertical by more than 15 degrees. It may bedesirable, for example, to arrange for the path of the tobacco as itapproaches the conveyor to be inclined to the vertical by at least 40degrees. However, it is usually convenient for the hopper of thecigarette making machine to project the tobacco vertically upwards intothe channel. As described in our British Patent specification No.2096876, the tobacco may be given an additional horizontal component ofmotion on or immediately before entering the channel by deflecting, bymeans of curved vanes, air flowing upwards into the channel. The airvelocity required for this purpose needs to be relatively high, and thiscan be achieved by means of the first aspect of this invention whileallowing for a reduction in the air velocity near the outlet (upper) endof the channel to reduce the impact velocity of tobacco on the conveyor.

According to another aspect of this invention, a cigarette makingmachine comprises means for forming a carpet of tobacco and forconveying the carpet pneumatically through a channel towards a conveyorto form a cigarette filler stream on the conveyor, characterised in thatthe channel extends around a cylindrical surface having an axis inclinedto the center line of a first part of the channel conveying the carpettowards the cylindrical surface, and that a second part of the channelwhich is arranged to convey the carpet after it has passed around thecylindrical surface has its center line inclined to that of the firstmentioned part of the channel and to the axis of the cylindricalsurface.

The motion of the tobacco passing around the cylindrical surface may becompared with the motion of a web passing around a turning bar. If theaxis of the cylindrical surface is set at 45 degrees to the horizontal,for example, then the path of the tobacco may initiallly be verticallyupwards and will then extend horizontally after passing around thecylindrical surface. This example in fact represents a preferred use ofthis aspect of this invention to enable tobacco to be delivered to theconveyor with a substantial component of movement in the direction ofmovement of the conveyor.

In a preferred machine according to this aspect of the invention, theupwardly extending inlet end portion of the channel is divided into twoparts which extend around two different cylindrical surfaces offset fromone another but inclined to the horizontal by the same angle, wherebythe outlet end portions of the two outlet channels lie side-by-side.Thus the tobacco passing through the two channels approaches theconveyor from opposite sides of a central vertical plane through theconveyor and, in the preferred arrangement, combines to form what may beregarded as a braid of tobacco on the conveyor.

Other aspects of this invention will be understood from the appendedclaims.

Examples of machines according to this invention are shown in theaccompanying drawings. In these drawings:

FIG. 1 is a diagrammatic front view of a machine embodying some aspectof this invention;

FIG. 2 is a diagrammatic front view of a second machine embodying thefirst aspect of this invention;

FIG. 3 is a diagrammatic front view of a machine embodying a furtheraspect of this invention;

FIG. 4 illustrates a modified form of channel for the machine shown inFIG. 3;

FIG. 5 is a diagrammatic view in the direction of the arrow V in FIG. 4;

FIG. 6 is a vertical section through the split channels provided by themodified arrangement shown in FIGS. 4 and 5, taken effectively at lineVI--VI in FIG. 3; and

FIG. 7 is a diagrammatic front view of another different machine.

FIG. 1 shows a cigarette making machine including a channel 10 throughwhich a carpet of tobacco is conveyed pneumatically upwards towards aconveyor 12 to form a cigarette filler stream 15 on the conveyor. Thefiller stream is trimmed by a trimmer 14 and is then deposited on awrapper web 16 carried by a garniture tape 18. The rear wall of thechannel includes a first louvre 20 near the inlet end of the channel,and a second louvre 22 near the outlet end of the channel. As usual withthis type of machine, the conveyor 12 is porous and has suction appliedto it from a suction chamber 24 so as to grip the tobacco arriving onthe conveyor.

Tobacco enters the lower end of the channel 10 in an upward directionand is deflected, so as to have a component of motion in the directionof movement of the conveyor 12, by air streams flowing into the lowerend of the channel between deflector vanes 26, the arrangement beinggenerally as described with reference to FIGS. 1 and 2 in our BritishPatent specification No. 2096876. It should be noted that the channel isinclined to the vertical, as shown in FIG. 1, by an angle which isapproximately 40 degrees.

In order to deflect the incoming tobacco, the initial air velocity needsto be relatively high. This is achieved by virtue of the fact that airis drawn in through the inlet of the channel as a result of suctionapplied to both of the louvres 20 and 22. However, above the louvre 20the air velocity is significantly lower and the tobacco velocity iscorrespondingly reduced, thus avoiding a high-velocity impact of tobaccoon the conveyor 12.

By way of example, suction may be applied to both louvres 20 and 22 fromthe same source, and the open areas and loss coefficients of the twolouvres may be similar. The term "loss coefficient" refers to a measureof the pressure drop through the respective louvres.

FIG. 2 shows a different machine. In this case, tobacco is conveyedpneumatically through a vertical channel 100 with the aid of suctionlouvres 110 and 120 towards a conveyor 130 of which the portion adjacentto outlet of the channel 100 is inclined to the channel by 45 degrees sothat the tobacco arriving on the conveyor again has a significantcomponent of motion in the direction of movement of the conveyor. Theconveyor in this case passes around three pulleys 140, 150 and 160 ofwhich the last is adjustable in the direction of the arrow 165 totension the conveyor. A cigarette filler stream formed on the conveyoris trimmed by a trimmer 170 and is then transferred from the conveyor istrimmed by a trimmer 170 and is then transferred from the conveyor by atransfer wheel 180 to a wrapper web 190. There is no need in this caseto deflect the tobacco as it enters the channel.

FIG. 3 shows a machine embodying a different aspect of this invention.Tobacco is conveyed pneumatically onto a conveyor 200 through a channelcomprising a vertical first portion 202, an approximately horizontalsecond portion 204 and a joining portion 206 which is notionally curvedaround a cylinder having an axis 208 inclined to the vertical by 45degrees; the radius of the cylinder is R. With this arrangement, thetobacco arrives at the conveyor with a major component of its movementin the direction of movement of the conveyor, the conveyor 200 being inthis example inclined to the horizontal by 15 degrees. As before, thecigarette filler stream 209 formed on the conveyor is trimmed by atrimmer 210 and is then deposited on a wrapper web 212.

As in the previous examples, there is a first louvre 214 lyingtransverse to the direction of movement of the tobacco through thechannel, and a second louvre 216 which is parallel to the conveyor 200.To compensate for the variable flow resistance for tobacco at variouspositions across the width of the channel (owing to the variable pathlength), the louvre 216 increases progressively in width towards thelower extremity of the channel, i.e. as the path length increases.Similar considerations apply to FIG. 2, but to a lesser extent.

Depending upon the relationships of the suction pressures at variouspoints in the system, especially above the conveyor 200 and in thesuction louvres, and upon other factors affecting the air flows, therate at which air is drawn through the conveyor 200 at any givenposition along the conveyor may need to be greater than the air flowrate at a corresponding position across the width of the channel. Inthis case, there should be provision to admit air into the channel 204at a position close to the tobacco stream on the conveyor, preferablyfrom both sides. The width of the air inlets would vary along theconveyor to admit the appropriate amount of air at each point. Inprinciple, it is possible for some positions along the conveyor torequire air inlets and no louvre, while at other positions the air flowcharacteristics require both a louvre and an inlet, or just a louvre.However, it is preferable to provide a louvre and an inlet alongsubstantially the entire length of the conveyor (ie, at the outlet fromthe channel 204).

FIG. 3 shows in addition a rotary brush 218 rotating about a verticalaxis to control the velocity of the tobacco entering the horizontalportion 204 of the channel. However, this brush may be omitted. Thefirst louvre 214 may, in principle, be omitted provided there is anadequate air flow through the channel 204 to convey the tobacco throughthe channel.

As a modification of the machine shown in FIG. 3, tobacco may bedelivered directly into the horizontal channel 204 by a tobacco feedapparatus as described with reference to FIGS. 1 to 5 in our BritishPatent specification No. 1296273.

In view of the small angle of inclination between the channel 204 andthe conveyor 200 (approximately 15 degrees), the channel has to berelatively narrow (i.e., dimension W is relatively small) to avoid aneed for an excessively long conveyor. As an alternative, the initialwidth of the channel may be doubled, without requiring a longerconveyor, if the channel is split to form two portions passing arounddifferent notational cylinders. This is explained below with referenceto FIGS. 4 and 5.

As shown in FIG. 4, a channel comprising a vertical first portion 300 ofwidth 2W is split longitudually into two portions 300A and 300Brespectively, each of width W, leading to horizontal second portions 302and 303 (of width W) via curved portions 304 and 306 respectively. Thismay be best understood with reference to FIG. 5, which shows in completeoutline the notional cylinders 308 and 310 around which the two curvedportions 304 and 306 respectively pass; these cylinders have axes 308Aand 310A which, as seen in FIG. 4, are inclined to the vertical by 45degrees. It should be noted that the cylinder 310 has a slightly smallerdiameter than the cylinder 208 so that the horizontal portion 302 isspaced from the portion 303. With this arrangement, a tobacco carpet ofwidth 2W can be conveyed pneumatically onto the conveyor 200 shown inFIG. 3. FIG. 6 shows a preferred way of achieving that.

FIG. 6 is a section on the line VI--VI in FIG. 3. It should beunderstood that it applies to a modified form of FIG. 3 in which thechannel is split as described above with reference to FIGS. 4 and 5.

In FIG. 6, the two side-by-side channel portions formed by the splitchannel shown in FIGS. 4 and 5 are identified by the reference numerals400 and 402 respectively. Tobacco carpets flowing through these channelsmerge in the region 404, producing a form of braid which is blown into atrough 406 by air jets (or by a continuous curtain of high-velocity air)blown upwards, in the direction of the arrow 408, from a space 410 whichmay be at atmospheric pressure. Above the trough 406 lies the conveyor412; as usual, suction is applied through the conveyor from a space (notshown) above the conveyor to hold tobacco on the conveyor.

The air admitted or blown in from the space 410 may also serves the samefunction as the air inlets described above with reference to FIG. 3.

Each channel portion 400 and 402 has a separate louvre 414 and 416respectively, corresponding to the louvre 216 shown in FIG. 3. Asmentioned with reference to FIG. 3 the width of each louvre may increaseprogressively as the path length for tobacco increases.

The depth of the trough 406 defined by fixed side walls 406A and 406Bincreases progressively to accommodate the increasing amount of tobaccoat various positons along the conveyor.

For the avoidance of doubt, it should be understood with reference toFIG. 6 that the motion of tobacco is nearly at right angles to the planeof the figure.

FIG. 7 shows a different machine in which a channel with a verticalfirst portion 500 of width 2W leads into two side-by-side portions 502of width W lying at 60 degrees to the vertical and extending towards aconveyor 504 lying at 45 degrees to the vertical. It should beunderstood that the bending of the channel portions in this instanceresults from an arrangement in which each channel passes around anotional cylinder having its axis inclined to the vertical by 30degrees. The channels may each include one or more louvres as describedwith reference to FIG. 3.

In FIG. 7 the cigarette filler stream is held on the conveyor 504suction while it passes around a pulley 506, is then trimmed by atrimmer 508 and is transferred to a wrapper web 512 by a suction wheel510.

In the examples of FIGS. 3 to 7, the arrival of the tobacco at theconveyor with a major component of motion in the direction of movementof the conveyor means that, apart from reducing damage to the tobacco,there is a reduced tendency (compared with prior machines) for thetobacco to be flattened on impact with the conveyor, or with tobaccoalready on the conveyor, with consequent aligning of the strands oftobacco in the direction of movement of the conveyor. Such aligningtends to reduce the firmness of the finished cigarette rod, so that moretobacco has to be used to provide a given firmness. Random orientationof the tobacco strands, on the other hand, which is promoted by thesubstantial "forward component" provided by the present invention in allits aspects enhances cigarette firmness and also ends retention.

Random orientation of tobacco strands is also promoted by the deepeningtrough described with reference to FIG. 6 (and also useful in thesimpler arrangement of FIG. 3). Tobacco strands arriving at the conveyorretain their random orientations instead of being sucked through therelatively narrow trough with a consequent tendency towards flatteningof the strands along the conveyor.

I claim:
 1. A cigarette making machine including a channel, a conveyorat the outlet of said channel, means for pneumatically conveying tobaccothrough said channel to form a cigarette filler stream on said conveyorby causing air and tobacco to enter the channel through its inlet end, afirst louvre through which some of the air entering the channel throughits inlet end is drawn from the channel while tobacco continues towardsthe conveyor, and a second louvre, closer than the first louvre to theoutlet end of the channel, through which an additional amount of the airentering the channel is drawn while tobacco continues towards theconveyor.
 2. A machine according to claim 1 in which the part of thechannel extending between the first louvre and the outlet end of thechannel is inclined to the conveyor so that tobacco will arrive at theconveyor with a component of movement in the direction of movement ofthe conveyor.
 3. A machine according to claim 2, further comprisingmeans including deflector vanes through which at least part of the airpasses on its way towards or into the channel for deflecting said air soas to have a component of movement in the direction of movement of theconveyor.
 4. A machine according to claim 3 including means fordelivering tobacco substantially vertically towards the inlet end of thechannel, said deflection vanes being operative to deflect the air suchthat the tobacco is given a horizontal component of movement by the airafter deflection thereof by said deflector vanes.
 5. A method of makingcigarettes, in which tobacco is conveyed pneumatically through a channelto form a cigarette filler stream on an air-pervious conveyor at theoutlet end of the channel, including the steps of drawing some of theair from the channel through a first louvre, and drawing a furtheramount of air from the channel through a second louvre closer than thefirst louvre to the outlet end of the channel, whereby the tobaccoparticles are accelerated by a relatively high velocity air streamflowing between the channel inlet and the first louvre and thereafterenter a lower velocity air stream between the first and second louvresso as to arrive at the conveyor with a relatively low velocity.
 6. Amethod according to claim 5 further including passing at least part ofthe air entering the channel through deflector vanes imparting to theair a component of movement in the direction of movement of theconveyor, and in which the tobacco is deflected by the air so as to havea similar component of movement.
 7. A cigarette making machinecomprising means for forming a carpet of tobacco and for conveying thecarpet pneumatically through a channel towards a conveyor to form acigarette filler stream on the conveyor, characterized in that thechannel extends around a part-cylindrical surface having an axisinclined to the center line of a first part of the channel conveying thecarpet towards the part-cylindrical surface, and that a second part ofthe channel which is arranged to convey the carpet after it has passedaround the part-cylindrical surface has its center line inclined to thatof the first part of the channel and to the axis of the part-cylindricalsurface.
 8. A cigarette making machine according to claim 7 in which theplanes of the first and second parts of the channel are parallel.
 9. Acigarette making machine according to claim 8 in which the first part ofthe channel lies in a substantially vertical plane and is arranged toconvey the carpet of tobacco upwards, the second part of the channelbeing arranged to convey the carpet in an approximately horizontaldirection.
 10. A cigarette making machine according to claim 7 in whichthe conveyor is arranged to receive the tobacco directly from thechannel and carries the thus-formed cigarette filler stream directlyonto a wrapper web in which the filler stream (or part remaining aftertrimming) is enclosed to form a continuous cigarette rod, the conveyorbeing inclined to the center line of the second part of the channel by asmall angle such that tobacco arrives at the conveyor with a majorcomponent of movement in the direction of movement of the conveyor. 11.A cigarette making machine according to claim 7 in which the first partof the channel is divided longitudually into two parts which extendaround two different part cylindrical surfaces offset from one buthaving substantially parallel axes, whereby the second portions of thechannel lie side-by-side so as to convey portions of the tobacco carpetwhich merge at or near the conveyor.
 12. A cigarette making machineaccording to claim 11 in which the two portions of the tobacco carpetmerge in a zone adjacent to a progressively deepening trough in whichthe cigarette filler stream, as it builds up on the conveyor, isconveyed by the conveyor with the aid of suction applied through theconveyor to grip the tobacco.
 13. A cigarette making machine comprising:means for forming a carpet of tobacco and for conveying the carpetpneumatically through a channel towards a conveyor to form a cigarettefiller stream on the conveyor, wherein the channel extends towards theconveyor and at a small angle thereto such that a major component of themovement of the tobacco as it reaches the conveyor is in the directionof movement of the conveyor, and wherein fixed side walls are providedadjacent to the conveyor to define a trough, for receiving the cigarettefiller stream, which increases progressively in depth so that its depthat each position along the conveyor is just sufficient substantially toaccommodate the quantity of tobacco at the conveyor at that position.